Prey concentration and temperature effect on budding and strobilation of Aurelia sp. 1 polyps

Abstract

Aurelia spp. are among the main blooming jellyfish species. The polyp stage plays an important role in its outbreaks. To determine how temperature and food conditions may affect the process of reproduction, we maintained Aurelia sp. 1 polyps in the laboratory at three temperatures (10–15°C) and four food concentrations (0–0.1 mg C l−1) to test their combined effects on the strobilation process and the production of buds and ephyrae. The length of the strobilation preparation period significantly decreased with increased temperature, but was not affected by food conditions. With sufficient food supply, the polyps that had already released ephyrae restart the strobilation process. Food condition positively affects both the production of buds and ephyrae. Temperature, however, had different effects: at the three temperatures tested, 13°C was most appropriate for polyps to release ephyrae, while bud production was highest at 15°C. These results suggest that eutrophication (as a proxy for food condition) would affect both the size of the Aurelia sp. 1 polyp population and juvenile medusa population, whereas temperature adjusts the reproductive energy distribution between budding and ephyra release to regulate the strobilation process. This temperature adjustment mechanism likely helps match the production of juvenile medusae with the peak of zooplankton biomass.